However, the initial conditions are a subtle issue, which is true not only in LQC but also in mLQCs.
This is mainly because that in general there does not exist a preferred initial time and state for a quantum field in an arbitrarily curved space-time [1]}.
If the universe is sufficiently smooth and its evolution is sufficiently slow, so that the characteristic scale of perturbations is much larger than the wavelengths
of all the relevant modes, a well justified initial
state can be defined: the BD vacuum. This is precisely the initial state commonly adopted in GR at the beginning of the slow-roll inflation,
in which all the relevant perturbation modes are well inside the
comoving Hubble radius [2]} [cf. Fig.REF ].
